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1 | #ifndef _LIBCOUNTER_SHM_H |
2 | #define _LIBCOUNTER_SHM_H | |
3 | ||
4 | /* | |
5 | * libcounter/shm.h | |
6 | * | |
7 | * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
8 | * | |
9 | * This library is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU Lesser General Public | |
11 | * License as published by the Free Software Foundation; only | |
12 | * version 2.1 of the License. | |
13 | * | |
14 | * This library is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * Lesser General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU Lesser General Public | |
20 | * License along with this library; if not, write to the Free Software | |
21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
22 | */ | |
23 | ||
24 | #include <stddef.h> | |
25 | #include <stdint.h> | |
26 | #include <unistd.h> | |
27 | #include <usterr-signal-safe.h> | |
28 | #include <urcu/compiler.h> | |
29 | #include "shm_types.h" | |
30 | ||
31 | /* lttng_counter_handle_create - for UST. */ | |
32 | extern | |
33 | struct lttng_counter_shm_handle *lttng_counter_handle_create(void *data, | |
34 | uint64_t memory_map_size, int wakeup_fd); | |
35 | /* lttng_counter_handle_add_cpu - for UST. */ | |
36 | extern | |
37 | int lttng_counter_handle_add_cpu(struct lttng_counter_shm_handle *handle, | |
38 | int shm_fd, uint32_t cpu_nr, | |
39 | uint64_t memory_map_size); | |
40 | unsigned int lttng_counter_handle_get_nr_cpus(struct lttng_counter_shm_handle *handle); | |
41 | ||
42 | /* | |
43 | * Pointer dereferencing. We don't trust the shm_ref, so we validate | |
44 | * both the index and offset with known boundaries. | |
45 | * | |
46 | * "shmp" and "shmp_index" guarantee that it's safe to use the pointer | |
47 | * target type, even in the occurrence of shm_ref modification by an | |
48 | * untrusted process having write access to the shm_ref. We return a | |
49 | * NULL pointer if the ranges are invalid. | |
50 | */ | |
51 | static inline | |
52 | char *_lttng_counter_shmp_offset(struct lttng_counter_shm_object_table *table, | |
53 | struct lttng_counter_shm_ref *ref, | |
54 | size_t idx, size_t elem_size) | |
55 | { | |
56 | struct lttng_counter_shm_object *obj; | |
57 | size_t objindex, ref_offset; | |
58 | ||
59 | objindex = (size_t) ref->index; | |
60 | if (caa_unlikely(objindex >= table->allocated_len)) | |
61 | return NULL; | |
62 | obj = &table->objects[objindex]; | |
63 | ref_offset = (size_t) ref->offset; | |
64 | ref_offset += idx * elem_size; | |
65 | /* Check if part of the element returned would exceed the limits. */ | |
66 | if (caa_unlikely(ref_offset + elem_size > obj->memory_map_size)) | |
67 | return NULL; | |
68 | return &obj->memory_map[ref_offset]; | |
69 | } | |
70 | ||
71 | #define lttng_counter_shmp_index(handle, ref, index) \ | |
72 | ({ \ | |
73 | __typeof__((ref)._type) ____ptr_ret; \ | |
74 | ____ptr_ret = (__typeof__(____ptr_ret)) _lttng_counter_shmp_offset((handle)->table, &(ref)._ref, index, sizeof(*____ptr_ret)); \ | |
75 | ____ptr_ret; \ | |
76 | }) | |
77 | ||
78 | #define lttng_counter_shmp(handle, ref) lttng_counter_shmp_index(handle, ref, 0) | |
79 | ||
80 | static inline | |
81 | void _lttng_counter_set_shmp(struct lttng_counter_shm_ref *ref, struct lttng_counter_shm_ref src) | |
82 | { | |
83 | *ref = src; | |
84 | } | |
85 | ||
86 | #define lttng_counter_set_shmp(ref, src) _lttng_counter_set_shmp(&(ref)._ref, src) | |
87 | ||
88 | struct lttng_counter_shm_object_table *lttng_counter_shm_object_table_create(size_t max_nb_obj); | |
89 | struct lttng_counter_shm_object *lttng_counter_shm_object_table_alloc(struct lttng_counter_shm_object_table *table, | |
90 | size_t memory_map_size, | |
91 | enum lttng_counter_shm_object_type type, | |
92 | const int cpu_fd, | |
93 | int cpu); | |
94 | struct lttng_counter_shm_object *lttng_counter_shm_object_table_append_shm(struct lttng_counter_shm_object_table *table, | |
95 | int shm_fd, size_t memory_map_size); | |
96 | /* mem ownership is passed to lttng_counter_shm_object_table_append_mem(). */ | |
97 | struct lttng_counter_shm_object *lttng_counter_shm_object_table_append_mem(struct lttng_counter_shm_object_table *table, | |
98 | void *mem, size_t memory_map_size); | |
99 | void lttng_counter_shm_object_table_destroy(struct lttng_counter_shm_object_table *table, int consumer); | |
100 | ||
101 | /* | |
102 | * lttng_counter_zalloc_shm - allocate memory within a shm object. | |
103 | * | |
104 | * Shared memory is already zeroed by shmget. | |
105 | * *NOT* multithread-safe (should be protected by mutex). | |
106 | * Returns a -1, -1 tuple on error. | |
107 | */ | |
108 | struct lttng_counter_shm_ref lttng_counter_zalloc_shm(struct lttng_counter_shm_object *obj, size_t len); | |
109 | void lttng_counter_align_shm(struct lttng_counter_shm_object *obj, size_t align); | |
110 | ||
111 | static inline | |
112 | int lttng_counter_shm_get_shm_fd(struct lttng_counter_shm_handle *handle, struct lttng_counter_shm_ref *ref) | |
113 | { | |
114 | struct lttng_counter_shm_object_table *table = handle->table; | |
115 | struct lttng_counter_shm_object *obj; | |
116 | size_t index; | |
117 | ||
118 | index = (size_t) ref->index; | |
119 | if (caa_unlikely(index >= table->allocated_len)) | |
120 | return -EPERM; | |
121 | obj = &table->objects[index]; | |
122 | return obj->shm_fd; | |
123 | } | |
124 | ||
125 | ||
126 | static inline | |
127 | int lttng_counter_shm_get_shm_size(struct lttng_counter_shm_handle *handle, struct lttng_counter_shm_ref *ref, | |
128 | uint64_t *size) | |
129 | { | |
130 | struct lttng_counter_shm_object_table *table = handle->table; | |
131 | struct lttng_counter_shm_object *obj; | |
132 | size_t index; | |
133 | ||
134 | index = (size_t) ref->index; | |
135 | if (caa_unlikely(index >= table->allocated_len)) | |
136 | return -EPERM; | |
137 | obj = &table->objects[index]; | |
138 | *size = obj->memory_map_size; | |
139 | return 0; | |
140 | } | |
141 | ||
142 | #endif /* _LIBCOUNTER_SHM_H */ |